Sundance has become a reliable way of taking the pulse of liberal America. Last year, the festival coincided with the inauguration of America's first black president. People seemed poised between fear and euphoria. Now the ski lodges and posh cafes are filled with sober, uncertain voices. Blue state Americans don't know what to think about the numerous setbacks of the last months, such as the defeat of healthcare. They want to know how to survive a terrible, seemingly open-ended recession.

For its part, the festival has reacted to flagging corporate sponsorship by loudly affirming its desire to return to roots. "THIS IS THE RENEWED REBELLION," proclaim the slogans at the beginning of each screening. "THE RECHARGED FIGHT AGAINST THE ESTABLISHMENT OF THE EXPECTED." But rebellion seems to be the wrong way of characterising what appears to be a tentative groping after style and solutions. People muttered about the merits of Four Lions, Chris Morris's comedy about blowing yourself up and at the screening I went to I heard ambivalent American titters. This may not be a moment for cultural innovation.

Celebrities are few and hard to spot. Bill Gates sent a Twitter message to the effect that the $4,000 he spent at Sundance (the cost of a ticket that gets you to the front of the queue at any screening) was the best bargain of his life. A film about (and also partly by) Banksy was shown semi-clandestinely, in a cheeky attempt to replicate the anti-marketing strategies of its subject. A well-coiffed but near anonymous Elton John was to be glimpsed at a party.

Far from renewing rebellion, the best fiction films at Sundance seemed bent on reclaiming the best of the past. Cyrus, directed and written by the Duplass brothers, begins in 1970s mode with John (an underemployed freelance film editor) caught masturbating in a messy apartment. She has come to tell him she's getting married again. Undeterred, John gets himself going again, bagging Molly at a party. The rest of the film recounts the bizarre, wholly dysfunctional three-way relationship involving Molly and John (crazy about each other) and Molly's seriously overweight, manipulative, seedy 22-year-old son, who composes music when not wrecking his mother's life by seeking to expel her lover. Not wholly convincingly, the film has a happy ending.

Holy Rollers is 1970s Scorsese in its dark Brooklyn nightclub and warehouses locations and muddied sound. But this is a terrific, wholly contemporary adaptation of the true, only-in-New York story involving Hassidic Jews and the smuggling of ecstasy. Rabbis, wig-wearing mothers and excruciating interpretations of the Torah are rendered respectfully.

Action takes place in the dark, disco-filled places where Seriously Bad Jews hang out. They convince Hassidim to go to sinful Amsterdam, secrete ecstasy tablets in their fur hats (they are told that the pills are medicinal and, naively, they believe it) and walk back through customs in Montreal.

Shmuel, the film's gawky, large-hatted and dreadlocked adolescent hero, is straight out of Malamud or early Roth. His struggles to get free are touching because, drug-smuggling notwithstanding, they seem serious, old-fashioned, so totally at odds with the present. And the film is astonishingly sexy, too.

Recently, American campaigning documentaries have focused on eco-horrors. This year, they encompassed subjects as diverse as nukes and America's flagging high school system. An improbable celebrity was Muhammad Yunus, wearing a tan waistcoat and a white shirt amid the assembled anoraks, promoting a film about the import of microcredit from Bangladesh, where it was invented, to Queens. The Nobel prize-winning Yunus is a patient and charismatic revolutionary. For millions, his innovative banking practices have come to be a way out of poverty. He thinks small-scale loans could transform the lives of America's poor, too.

Audiences cheered Freedom Riders, an eloquent account of those who were brave or rash enough to carry the cause of desegregation to the racist heart of the south in 1961, riding Greyhound or Trailways buses. It's astonishing how well these would-be martyrs have aged and their testimony makes one believe that these exploits happened yesterday rather than representing a now distant, more optimistic America. One might expect such a film to depict the Kennedy brothers and Martin Luther King as heroes; instead, Stanley Nelson shows them to be caught up by events, looking worse and worse as they attempt to broker compromises until the spirit of the riders sweeps them away.

By contrast, audiences were stunned by Alex Gibney's detailed account of congressional corruption in Casino Jack and the United States of Money. I'm not sure why the exploits of Jack Abramoff, lobbyist extraordinary, aren't well known in Britain. He was a one-man black hole of the Bush years, taking over Congress, funnelling money and freebies everywhere. Gibney is a tough investigative journalist in the best American tradition. He was at pains to point out that the Abramoff story wasn't history. "The Supreme Court has just removed limits on campaign funding," he said, gloomily. "I'm not sure that people realise what this means. You have to realise that the power of money could further dominate American life."

Sundance is at its best when it is most bizarrely unexpected. Danish film The Red Chapel chronicles the official visit of a pair of stand-up comedians to North Korea, and the incomprehension of their minder, Mrs Pac, confronted by whoopee cushions and clog-dancing. This year's Cinderellas of Sundance were the Australian cane toads depicted by Mark Lewis in glorious 3-D in Cane Toads: The Conquest. After being introduced in the 1930s from Hawaii, they invaded most of Australia, carpeting entire towns. Although locals hunt them, dogs who sniff them experience ecstasy. In recession-era America, these toads seem benign, even lovable.